Here’s a quote, dubiously attributed to Charles Bukowski, that seems appropriate to the local political scene.
“The problem with the world is that the intelligent people are full of doubt, while stupid ones are full of confidence.”
Or, here’s the more refined, less forceful, version, from Bertrand Russell.
The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt.
The best lack all conviction, while the worst
Are full of passionate intensity.
http://www.poetryfoundation.org/poem/172062
Excellent.